Wubs GP32 - Nand replacement.

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rubber_jonnie
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Wubs GP32 - Nand replacement.

Post by rubber_jonnie »

So I was contacted a short while ago by Wub about his GP32, which had died.

Having done the diagnostic work, it's believed that the fault is a bad NAND IC, so we got to chatting and I've agreed that I'll do the repair for free on the basis of it being content for the forum.

The GP32 arrived a couple of days ago, but I've been away, but once home I've had a look through the necessary procedures, and it looks reasonably simple. Program new chip, remove old chip, install new chip.

First off, I don't have a suitable TSOP adapter to allow me to program the new NAND that Wub supplied, but that's now on order, but I'll get started while I wait by removing the old one and prepping the board ready for the new one.

Pics to follow but I wanted to get a holding post in place so I'm ready to go.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Wubs GP32 - Nand replacement.

Post by rubber_jonnie »

Ok, so I've got started in anticipation of getting the TSOP adapter so I can flash the new Nand and get it installed.

The console itself just does this on boot:

IMG20240902143432.jpg
IMG20240902143432.jpg (212.76 KiB) Viewed 248 times

So it's definitely dead Jim...


Opening it up is simple since it just uses philips screws to hold it all together, 8 in total, 6 for the case and 2 internal screws for the grey plastic bezel around the middle.

Inside I found this:

IMG20240902143636.jpg
IMG20240902143636.jpg (293.74 KiB) Viewed 248 times

Which is the external switch for the display light held in by some sort of modelling epoxy putty. The wires simply connect the front light to the console's power.

IMG20240902143647.jpg
IMG20240902143647.jpg (404.86 KiB) Viewed 248 times

Being a front lit unit I wanted to be extra careful as I didn't want to damage the light during disassembly, so I disconnected the red and orange wires from the switch and the black wire from the PCB.

The next step I took was to disconnect the PCB from the display. There are 4 clips like this:

IMG20240902144202.jpg
IMG20240902144202.jpg (207.1 KiB) Viewed 248 times

These hold the display to the PCB. The display ribbon has a lift type lock on it, and it's very stiff so you have to be careful not to break it.

Again, not my console so I wanted to tread carefully with the display, and one final item to remove is the joypad, which can be pulled off the fully micro switched joystick and is the last thing before the PCB will lift out:

IMG20240902144349.jpg
IMG20240902144349.jpg (129.61 KiB) Viewed 248 times

This is the failed part:

IMG20240902144716.jpg
IMG20240902144716.jpg (305.42 KiB) Viewed 248 times

So I prepped the board to make sure hot air wouldn't damage the display connector or joystick:

IMG20240902145050.jpg
IMG20240902145050.jpg (294.45 KiB) Viewed 248 times

And I added some leaded solder to the legs and used hot air at about 300C to lift the chip off taking great care to heat evenly to avoid 'popcorning' the PCB:

IMG20240902150246.jpg
IMG20240902150246.jpg (180.49 KiB) Viewed 248 times

It came away great and the board cleaned up nicely, ready for the new one:

IMG20240902150239.jpg
IMG20240902150239.jpg (289.9 KiB) Viewed 248 times

Just need to wait for the TSOP adapter to arrive and we're ready to go. Hopefully it won't take too long. It's a ZIF socket type, so I at least won't have to solder the Nand to program it.

My own GP32 is still fine, and is a Back Light Unit or BLU, so slightly different to Wubs.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Wubs GP32 - Nand replacement.

Post by wub »

Thanks so much to Jon for taking this on! I've made a small donation to the site as a way of saying thank you.

It's hard to overstate how incredible it was to have one of these in the early 2000's so I'm hoping that this memory IC is the only thing that's wrong. The GP32 might look weird but that clicky dpad actually worked very well!

It's great to see the old chip is already off the board, I can't wait to see the next installment of this!
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Re: Wubs GP32 - Nand replacement.

Post by stephen_usher »

Well, after he's replaced that memory it will be a flashy hand-held again! ;-) *I'll get my coat*
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Re: Wubs GP32 - Nand replacement.

Post by rubber_jonnie »

wub wrote: Mon Sep 02, 2024 7:05 pm Thanks so much to Jon for taking this on! I've made a small donation to the site as a way of saying thank you.

It's hard to overstate how incredible it was to have one of these in the early 2000's so I'm hoping that this memory IC is the only thing that's wrong. The GP32 might look weird but that clicky dpad actually worked very well!

It's great to see the old chip is already off the board, I can't wait to see the next installment of this!
No worries, I'm happy to be doing a bit of a different repair and it's good content for the site 😁
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Wubs GP32 - Nand replacement.

Post by rubber_jonnie »

stephen_usher wrote: Mon Sep 02, 2024 7:45 pm Well, after he's replaced that memory it will be a flashy hand-held again! ;-) *I'll get my coat*
:dizzy:
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Wubs GP32 - Nand replacement.

Post by wub »

stephen_usher wrote: Mon Sep 02, 2024 7:45 pm Well, after he's replaced that memory it will be a flashy hand-held again! ;-) *I'll get my coat*
lol! :D
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Re: Wubs GP32 - Nand replacement.

Post by rubber_jonnie »

wub wrote: Mon Sep 02, 2024 7:05 pm
It's hard to overstate how incredible it was to have one of these in the early 2000's
Yes, they are a very nice machine, and so cool to have a tiny handheld that would run Doom comfortably and also that would allow for overclocking out of the box.

I also have the follow up, a GP2x, which was similarly cool and better specced, but IMHO lacked a bit of the charm of the GP32.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Wubs GP32 - Nand replacement.

Post by alexh »

I'm surprised the NAND was faulty rather than having just lost it's contents. It might have worked had it just been reprogrammed?
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Re: Wubs GP32 - Nand replacement.

Post by wub »

rubber_jonnie wrote: Tue Sep 03, 2024 9:08 am Yes, they are a very nice machine, and so cool to have a tiny handheld that would run Doom comfortably and also that would allow for overclocking out of the box.

I also have the follow up, a GP2x, which was similarly cool and better specced, but IMHO lacked a bit of the charm of the GP32.
Along with being so quirky looking I think the GP32 had the benefit of being very cheap at the time. My first non-lit unit was £103 from Lik Sang which was pretty amazing. The GP2X was more expensive but didn't seem quite worth it to me, same with the subsequent Canoo and Wiz. The GP32 also had the benefit of a very vibrant and active scene of developers and users, with regular programming competitions and just a lot of excitement and buzz around it. None of the followups could match that atmosphere!
alexh wrote: Tue Sep 03, 2024 3:15 pm I'm surprised the NAND was faulty rather than having just lost it's contents. It might have worked had it just been reprogrammed?
I'm going from memory as I was researching this repair a few years ago now, but I think the chips that were used in the earlier units were sub-standard and tended to lose the data over time if the unit is not kept with batteries in. I also have a BLU+ unit with the proper back-lit screen and I'm hoping that one does just need re-flashing as the bios is only slightly corrupted.

I went the other way to Jon with this and built a JTAG cable to do the flash with the software that was released on a long dead website called cobbleware. The thing I got stuck with is you need a PC old enough to have a proper parallel port, running linux, and my designated PC decided to die just as the JTAG cable was ready to test. It was around that time that Jon posted about his handheld collection here on Exxos and I started the conversation with him that led to him taking on the full repair.

So short answer is yes, a re-flash may well be enough to bring one of these back to life in some cases.
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